Concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer as well as preparation method and application of concrete viscosity reducer

Abstract

The invention provides a concrete viscosity reducer based on a perfluoroalkyl ethyl acrylate copolymer and a preparation method and application thereof.The preparation method comprises the steps that under the nitrogen protection condition, perfluoroalkyl ethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate are added into a solvent to serve as a base material, stirring and dissolving are conducted under the heating condition, and then the base material serves as a curing agent; dropwise adding a persulfate solution, carrying out heat preservation reaction, dialyzing a product after the reaction is finished, and drying to obtain the concrete viscosity reducer of the perfluoroalkyl ethyl acrylate copolymer. Compared with the prior art, an acrylate part in the perfluoroalkyl ethyl acrylate has certain polarity and can interact with the surfaces of cement particles. The perfluorinated chain segments are directionally adsorbed on the surfaces of cement particles, so that the surface energy of the cement particles is reduced, a low-friction interface layer is formed on the surface of the cement, and the hydrophilic chain segments in the copolymer have a steric hindrance effect, so that the agglomeration of the cement particles is inhibited, and the viscosity of concrete is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete admixtures, and in particular relates to a concrete viscosity reducer based on a perfluoroalkyl ethyl acrylate copolymer, and a preparation method and application thereof, for reducing the viscosity of high-grade concrete mixtures. Background Art

[0002] High-grade concrete has a low water-cement ratio, and has the characteristics of high viscosity, poor fluidity, and poor pumpability. In the application of construction projects, it often affects the construction efficiency of concrete. It also causes uneven formwork filling and leads to insufficient strength of concrete. These problems have attracted the attention of engineering researchers in the field of construction.

[0003] Currently, the primary method for reducing concrete viscosity is to increase the dosage of viscosity reducers. Existing technologies primarily include surfactant-based viscosity reducers, polymer-based viscosity reducers, and mineral admixture-based viscosity reducers. Polymer-based viscosity reducers are the most widely used, achieving significant viscosity reduction effects at low dosages, with minimal impact on concrete strength and strong adaptability.

[0004] Patent publication number CN 112940197 A, published on June 11, 2021, discloses a polymer for viscosity-reducing and mud-resistant concrete and its preparation method. The polymer raw material is primarily composed of the following components, calculated based on 1000 parts by weight: 68.18-69.95 parts of alcohol head, 142.76-146.52 parts of cyclic monomer, 0.9-2.2 parts of catalyst, 170.06-174.53 parts of unsaturated sulfonate monomer, 6.1-8.3 parts of reducing agent, 5.2-9.4 parts of initiator, 7.1-11.9 parts of neutralizing agent, 4.7-6.5 parts of chain transfer agent, and the balance being water. However, the preparation process is complex, making it unsuitable for industrial production. Summary of the Invention

[0005] The present invention provides a concrete viscosity reducer based on a perfluoroalkyl ethyl acrylate copolymer and a preparation method thereof. Perfluoroalkyl ethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate are mixed with persulfate and reacted under heating conditions to obtain the perfluoroalkyl ethyl acrylate viscosity reducer. The preparation method is simple, efficient, suitable for industrial production, and has broad application prospects.

[0006] The present invention also provides an application of a concrete viscosity reducer based on a perfluoroalkyl ethyl acrylate copolymer, which is used for concrete.

[0007] The specific technical solutions of the present invention are as follows:

[0008] A concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, the structural formula of which is as follows:

[0009] Among them, the range of a is 1 to 5, the range of b is 20 to 50, and the range of c is 30 to 60;

[0010] The relative molecular mass of the concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer is 7000-17000.

[0011] The present invention provides a method for preparing a concrete viscosity reducer based on a perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0012] Under nitrogen protection conditions, perfluoroalkyl ethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate are added to a solvent as a base material, stirred and dissolved under heating conditions, a persulfate solution is added dropwise, and the temperature is kept for reaction. After the reaction is completed, the product is dialyzed and dried to obtain a concrete viscosity reducer of a perfluoroalkyl ethyl acrylate copolymer.

[0013] In the primer, the molar ratio of perfluoroalkylethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate is 20-50:30-60:1-5; preferably 45:45:2.5;

[0014] The molecular structure of the fluoroalkyl ethyl acrylate is as follows:

[0015]

[0016] Its chemical structural formula is as follows: C6H7F3O2, and the relative molecular mass of the perfluoroalkyl ethyl acrylate is 168.12.

[0017] The molecular structural formula of the hydroxyethyl acrylate is as follows:

[0018]

[0019] The molecular structural formula of glycidyl methacrylate is as follows:

[0020]

[0021] In the primer, the mass concentration of the perfluoroalkylethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate as solutes is 40-65%;

[0022] The mass ratio of the solvent to the persulfate in the persulfate solution is 200:9.

[0023] The solvent is an ethanol solution with a mass concentration of 80%-90%;

[0024] The heating conditions mentioned above refer to heating at 70-80°C.

[0025] The time for adding persulfate solution is 6-7h;

[0026] The heat preservation reaction refers to the heat preservation reaction at 70-80°C for 1-1.5 hours;

[0027] The mass concentration of the persulfate solution is 9%, and the persulfate is one or more of ammonium persulfate, potassium persulfate, and sodium persulfate, preferably ammonium persulfate.

[0028] Preferably, the preparation method is:

[0029] Under nitrogen protection, perfluoroalkyl ethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate are added to a solvent as a base material, stirred and dissolved under heating conditions, and a persulfate solution is added dropwise. The reaction is kept warm. After the reaction is completed, the product is dialyzed and dried to obtain a perfluoroalkyl ethyl acrylate viscosity reducing agent.

[0030] In the present invention, a fluorinated alkyl monomer is graft-copolymerized with other monomers in a reaction to generate a copolymer. In the concrete, the perfluorinated chain segments of the copolymer are directionally adsorbed on the surface of cement particles, reducing the surface energy of the cement particles and forming a low-friction interface layer on the cement surface. The hydrophilic segments in the copolymer have a steric hindrance effect that inhibits the agglomeration of cement particles and reduces the viscosity of the concrete.

[0031] The present invention provides an application of a concrete viscosity reducer based on a perfluoroalkyl ethyl acrylate copolymer, which is used for concrete.

[0032] Compared to existing technologies, the acrylate portion of the perfluoroalkylethyl acrylate used in this invention exhibits a certain degree of polarity, allowing it to interact with the surface of cement particles. The perfluorochain segments are directionally adsorbed onto the cement particle surface, reducing the surface energy and forming a low-friction interface layer. The hydrophilic segments in the copolymer provide a steric hindrance effect, inhibiting the aggregation of cement particles and lowering the viscosity of the concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 For Example 8 13 C NMR test spectrum; 178-180 ppm is the -C=O peak, 121-129 ppm is the -CF peak.

[0034] Figure 2 For Example 8 1 H NMR test spectrum; the 2.9-3.0 ppm peak is -OH.

[0035] Figure 3This is the 19F NMR test spectrum of Example 8, wherein -65.58 ppm is the -CF3 peak. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0038] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0039] Example 1

[0040] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0041] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate were added to a four-necked flask in a molar ratio of 25:35:2.5, and an 80% ethanol solution was added as a solvent. At this time, the mass concentration of perfluoroalkylethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate as solutes was 46%. The stirring device was turned on, nitrogen was introduced, and the temperature was raised to 75°C. After all the monomers were dissolved, material A was added dropwise. Material A was a 9% ammonium persulfate solution. The mass ratio of the 80% ethanol solution to the persulfate in the persulfate solution was 200:9. Material A was added dropwise for 360 minutes. After the addition, the mixture was kept warm for 60 minutes and cooled to obtain the first product. The product was dialyzed and purified using deionized water as the dialyzate and ethanol as the buffer. A dialysis bag with a molecular weight cut-off of 15,000 was selected for dialysis. The dialyzate was replaced every 6 hours, and the dialysis purification was carried out for 12 hours. The purified product was dried at a constant temperature of 70° C. for 1 h to obtain a perfluoroalkyl ethyl acrylate copolymer.

[0042] Example 2

[0043] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0044] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 25:45:3.5. An 80% ethanol solution was added as a solvent, resulting in a 50% mass concentration of the solutes. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After the monomers were completely dissolved, material A was added dropwise. Material A consisted of a 9% ammonium persulfate solution with a mass ratio of 200:9 between the 80% ethanol solution and the persulfate in the persulfate solution. Material A was added dropwise for 360 minutes. After the addition, the mixture was kept warm for 60 minutes and cooled to obtain the first product. The first product was dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The perfluoroalkylethyl acrylate copolymer was then dried at 70°C for 1 hour.

[0045] Example 3

[0046] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0047] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 25:55:4.5. An 80% ethanol solution was added as a solvent, resulting in a solute concentration of 53% perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After complete dissolution of the monomers, material A was added dropwise. Material A consisted of a 9% ammonium persulfate solution with a mass ratio of 200:9 between the 80% ethanol solution and the persulfate in the persulfate solution. Material A was added dropwise for 360 minutes, followed by a 60-minute heat-retention reaction. The product was cooled to obtain the first product, which was then dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The product was then dried at 70°C for 1 hour to obtain a perfluoroalkylethyl acrylate copolymer.

[0048] Example 4

[0049] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0050] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 35:35:3.5. An 80% ethanol solution was added as a solvent, resulting in a solute concentration of 51% perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After complete dissolution of the monomers, material A was added dropwise. Material A consisted of a 9% ammonium persulfate solution with a mass ratio of 200:9 between the 80% ethanol solution and the persulfate in the persulfate solution. Material A was added dropwise for 360 minutes. After addition, the mixture was kept warm for 60 minutes and cooled to obtain the first product. The first product was dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The perfluoroalkylethyl acrylate copolymer was then dried at 70°C for 1 hour.

[0051] Example 5

[0052] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0053] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 35:45:4.5. An 80% ethanol solution was added as a solvent, resulting in a solute concentration of 54% perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After complete dissolution of the monomers, material A was added dropwise. Material A consisted of a 9% ammonium persulfate solution with a mass ratio of 200:9 between the 80% ethanol solution and the persulfate in the persulfate solution. Material A was added dropwise for 360 minutes. After addition, the mixture was kept warm for 60 minutes and cooled to obtain the first product. The first product was dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The perfluoroalkylethyl acrylate copolymer was then dried at 70°C for 1 hour.

[0054] Example 6

[0055] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0056] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 35:55:2.5. An 80% ethanol solution was added as a solvent, resulting in a solute concentration of 56% perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After complete dissolution of the monomers, material A was added dropwise. Material A consisted of a 9% ammonium persulfate solution with a mass ratio of 200:9 between the 80% ethanol solution and the persulfate in the persulfate solution. Material A was added dropwise for 360 minutes. After addition, the mixture was kept warm for 60 minutes and cooled to obtain the first product. The first product was dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The perfluoroalkylethyl acrylate copolymer was then dried at 70°C for 1 hour.

[0057] Example 7

[0058] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0059] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 45:35:4.5. An 80% ethanol solution was added as a solvent, resulting in a solute concentration of 55% perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After complete dissolution of the monomers, a 9% ammonium persulfate solution was added dropwise. The mass ratio of the 80% ethanol solution to the persulfate solution was 200:9. Material A was added dropwise for 360 minutes. After the addition, the mixture was kept warm for 60 minutes and cooled to obtain the first product. The first product was dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The product was then dried at 70°C for 1 hour to obtain a perfluoroalkylethyl acrylate copolymer.

[0060] Example 8

[0061] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0062] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 45:45:2.5. An 80% ethanol solution was added as a solvent, resulting in a solute concentration of 57% perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After complete dissolution of the monomers, material A was added dropwise. Material A consisted of a 9% ammonium persulfate solution with a mass ratio of 200:9 between the 80% ethanol solution and the persulfate in the persulfate solution. Material A was added dropwise for 360 minutes. After addition, the mixture was kept warm for 60 minutes and cooled to obtain the first product. The first product was dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The perfluoroalkylethyl acrylate copolymer was then dried at 70°C for 1 hour.

[0063] Figure 1 For Example 8 13 C NMR test spectrum; 178-180 ppm is the -C=O peak, 121-129 ppm is the -CF peak. Figure 2 For Example 8 1 H NMR test spectrum; the 2.9-3.0 ppm peak is -OH. Figure 3 This is the 19F NMR test spectrum of Example 8, wherein -65.58 ppm is the -CF3 peak, indicating that the preparation of the present invention is successful.

[0064] Example 9

[0065] A method for preparing a concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, specifically comprising:

[0066] Perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate were added to a four-necked flask at a molar ratio of 45:55:3.5. An 80% ethanol solution was added as a solvent, resulting in a solute concentration of 59% perfluoroalkylethyl acrylate, hydroxyethyl acrylate, and glycidyl methacrylate. A stirring device was activated, nitrogen was introduced, and the temperature was raised to 75°C. After complete dissolution of the monomers, material A was added dropwise. Material A consisted of a 9% ammonium persulfate solution with a mass ratio of 200:9 between the 80% ethanol solution and the persulfate in the persulfate solution. Material A was added dropwise for 360 minutes, followed by a 60-minute heat-retention reaction. The product was cooled to obtain a first product. The first product was dialyzed using deionized water as the dialyzate and ethanol as the buffer using a dialysis bag with a molecular weight cut-off of 15,000. The dialyzate was replaced every 6 hours for 12 hours. The product was then dried at 70°C for 1 hour to obtain a perfluoroalkylethyl acrylate copolymer.

[0067] Blank example 1

[0068] Concrete without the addition of perfluoroalkylethyl acrylate copolymer viscosity reducer.

[0069] Comparative Example 1

[0070] Add 1% of the mass of water reducer to the concrete with a concentration of 10% sodium a-olefin sulfonate foaming agent.

[0071] To evaluate the performance of the perfluoroalkylethyl acrylate copolymers of the present invention, Examples 1-9 were incorporated into a commercially available polycarboxylate water-reducing agent for comparison with a blank example 1 (water-reducing agent without the perfluoroalkylethyl acrylate copolymer) and a comparative example 1 (polycarboxylate water-reducing agent) in which a 10% sodium α-olefin sulfonate foaming agent was added, representing 1% of the mass of the commercially available polycarboxylate water-reducing agent. The perfluoroalkylethyl acrylate copolymers of Examples 1-9 were diluted to a 10% solution and then incorporated into the commercially available polycarboxylate water-reducing agent at a concentration of 1% of the mass of the water-reducing agent. Standard cement was used, and the water-reducing agent was used at a concentration of 3.2% of the mass of the cement. Concrete slump, expansion, collapse and emptying, and the 28-day compressive strength of concrete cubes were measured according to GB8076-2008 "Concrete Admixtures," GB / T50080-2016 "Standard for Testing Methods of Ordinary Concrete Mixtures," and GB / T50107-2013 "Standard for Testing and Evaluating Concrete Strength." L-box flow time and V-funnel flow time were tested according to the methods described in "Analysis of the Viscosity Evaluation Method of Polycarboxylic Acid Concrete," Lin Tianxing, Chen Xiaobin / / 16th Member Representative Conference of the Concrete Admixture Branch of the China Building Materials Federation and Seminar on Sustainable Development and Application Technology of Concrete and Admixtures. China Silicate Society, China Building Materials Federation, 2018. The cement used in this experiment was Conch Cement PO42.5, medium sand with a fineness modulus of 2.5, and continuously graded gravel with a diameter of 5-20 mm. Specific concrete raw materials and weight percentages are shown in Table 1.

[0072] Table 1 C50 concrete mass mix ratio (parts)

[0073] cement fly ash Mineral powder medium sand gravel water water reducer 380 60 50 650 1000 160 16

[0074] Table 2 Comparison of concrete properties

[0075]

[0076] The results in Table 2 show that, under the same conditions, the concrete prepared in Examples 1-9 according to the present invention exhibited greater slump and spread, shorter collapse and emptying times, L-box flow times, and V-funnel flow times, compared to Blank Example 1 and Comparative Example 1. Furthermore, the concrete specimens achieved a 28-day compressive strength that met the standard, demonstrating that the perfluoroalkylethyl acrylate copolymer prepared according to the present invention exhibits excellent viscosity-reducing properties and that the concrete specimens achieved a 28-day compressive strength that met the standard.

[0077] The perfluoro(Rf) alkyl group in the present invention has extremely low surface tension. It is copolymerized with acrylates to prepare a perfluoroalkyl ethyl acrylate copolymer viscosity reducer. The copolymer can reduce interfacial energy by adsorbing on the surface of cement particles, weakening the friction between cement particles, thereby reducing the viscosity of concrete and improving the fluidity and workability of concrete.

[0078] The above embodiments are described to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer, characterized in that: The structural formula of the concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer is as follows: Among them, the range of a is 1 to 5, the range of b is 20 to 50, and the range of c is 30 to 60.

2. The concrete viscosity reducer based on perfluoroalkylethyl acrylate copolymer according to claim 1, characterized in that: The relative molecular mass of the concrete viscosity reducer based on perfluoroalkyl ethyl acrylate copolymer is 7000-17000.

3. A method for preparing a concrete viscosity reducer based on a perfluoroalkylethyl acrylate copolymer according to claim 1 or 2, characterized in that: The preparation method is: Under nitrogen protection conditions, perfluoroalkyl ethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate are added to a solvent as a base material, stirred and dissolved under heating conditions, a persulfate solution is added dropwise, and the temperature is kept for reaction. After the reaction is completed, the product is dialyzed and dried to obtain a concrete viscosity reducer of a perfluoroalkyl ethyl acrylate copolymer.

4. The preparation method according to claim 3, characterized in that In the primer, the molar ratio of the perfluoroalkyl ethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate is 20-50:30-60:1-5.

5. The preparation method according to claim 3 or 4, characterized in that In the primer, the mass concentration of the perfluoroalkylethyl acrylate, hydroxyethyl acrylate and glycidyl methacrylate as solutes is 40-65%.

6. The preparation method according to claim 3 or 4, characterized in that The mass ratio of the solvent to the persulfate in the persulfate solution is 200:

9.

7. The preparation method according to claim 3 or 4, characterized in that The solvent is an ethanol solution with a mass concentration of 80%-90%.

8. The preparation method according to claim 3 or 4, characterized in that The heating conditions mentioned above refer to heating at 70-80°C.

9. The preparation method according to claim 3 or 4, characterized in that The time for adding the persulfate solution dropwise is 6-7 hours; the heat preservation reaction refers to the heat preservation reaction at 70-80°C for 1-1.5 hours.

10. Use of a concrete viscosity reducer based on a perfluoroalkylethyl acrylate copolymer according to claim 1 or 2, characterized in that: For concrete.

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